Machine tool

ABSTRACT

A machine tool capable of performing an accurate machining by preventing a second saddle  6  from displacing aslant to suppress the vibrations of a spindle head  8,  wherein a column  2  is fixedly installed on a bed  1,  a first saddle  4  is movably guided by the column  2  in vertical direction f 1,  a second saddle  6  is movably guided by the first saddle  4  in lateral direction f 2,  a spindle head  8  is movably guided by the second saddle  6  in longitudinal direction f 3,  and guide route means  5 A,  5 B,  5 C for guiding the second saddle  6  in lateral direction f 2  are formed at the rear lower position of the first saddle  4  as well as at the front upper and lower positions of the first saddle  4.

FIELD OF THE INVENTION

[0001] The present invention relates to a machine tool increasing inposition stability of a spindle.

BACKGROUND OF THE INVENTION

[0002] A machine tool capable of shortening the length of spindledirection (longitudinal direction) of a first saddle, a second saddleand a column as well as speeding up the longitudinal feed of a spindlehead, wherein the column is fixedly on a bed, the first saddle ismovably guided by the column in vertical direction, the second saddle ismovably guided by the first saddle in lateral direction, and the spindlehead is movably guided by the second saddle in longitudinal direction,has been known (See Japanese Patent Provisional Publication No. 365529of 1992, for example).

[0003] In this machine tool, when the first saddle and the second saddleare moved in vertical and lateral direction or when the spindle head ismoved in longitudinal direction, the second saddle is hard to attemptthe position stability. Unless the second saddle has sufficient positionstability, there occurs the problem that a spindle vibrates and workingcan not be carried out high-accurately.

[0004] The present invention aims to provide a machine tool that cansettle the problem.

SUMMARY OF THE INVENTION

[0005] To achieve the above-mentioned purpose, the invention ischaracterized by a machine tool wherein a column is fixedly installed ona bed, a first saddle is movably guided by the column in verticaldirection, a second saddle is movably guided by the first saddle inlateral direction, a spindle head is movably guided by the second saddlein longitudinal direction, and guide route means for guiding the secondsaddle in lateral direction are formed at the rear upper and lowerpositions of the first saddle or at either thereof as well as at thefront upper and lower positions of the first saddle.

[0006] According to this, the first saddle guides the second saddlethrough at least three guide route means. Besides, two opposite guideroute means in longitudinal direction among these have longitudinalfloating regulated by the second saddle part therebetween strictly.Therefore, the second saddle can secure position stability at anoptional position in the lateral moving range thereof.

[0007] This invention is preferably made as shown in claim 2. That is,the machine tool is constituted so that the column is fixedly installedon the bed, the first saddle is movably guided by the column in verticaldirection, the second saddle is movably guided by the first saddle inlateral direction, the spindle head is movably guided by the secondsaddle in longitudinal direction, and guide route means for guiding thesecond saddle in lateral direction are formed at the rear lower positionof the first saddle as well as at the front upper and lower positions ofthe first saddle.

[0008] According to this, when the bottom of the second saddle isreinforced as a spindle head supporting member, the supporting membereffectively contributes as a support structure of two guide route meansat the lower position of the first saddle and transmits floating controlforce of two guide route means to the second saddle.

[0009] These inventions are materialized as follows. That is, as shownin claim 3, the guide route means comprise route members andinterfitting members that slidably move with fitted in the routemembers. In this case, the route members are fixed on the first saddleor the second saddle. Besides, the interfitting members are fixed on thesecond saddle when the route members are fixed on the first saddle, andon the first saddle when the route member are fixed on the second saddleas well.

[0010] According to this, the guide route means are easily formed bywell-known means, and the route members and the interfitting members canrelatively slide on the first saddle to the second saddle in the statewhere floating is controlled.

[0011] Besides, as shown in claim 4, the guide route means for guidingthe second saddle in lateral direction comprises the route members andthe interfitting members that slidably move with fitted in the routemembers. The route members are fixed on the front upper and lowerpositions of the first saddle and a plurality of interfitting membersfixed on the second saddle are fitted in the route members. Besides, theroute members is fixed on the rear lower position of the first saddleand the singular or plural interfitting members fixed on the secondsaddle are fitted in the route members.

[0012] According to this, the second saddle effectively and simplyincreases in position stability without accompanying with enlargement ofthe whole construction.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a side view of a machine tool concerning the firstembodiment of the invention, FIG. 2 is a front view thereof, and FIG. 3is a plan view thereof.

[0014]FIG. 4 is a perspective view of an important part of the machinetool. FIG. 5 is a sectional view taken on line X-X in FIG. 2 at a sidesight, showing an important part of the machine tool.

[0015]FIG. 6 illustrates guide route means of the machine tool, FIG. 6Ais a perspective view, and FIG. 6B is a sectional view taken on lineX1-X1.

[0016]FIG. 7 is an operating explanatory view showing the state that aspindle head of the machine tool is moved to the forefront within amovable range to the second saddle.

PREFERRED EMBODIMENT OF THE INVENTION

[0017] The invention will be described with reference to the drawings.

[0018] In this embodiment, a machine tool comprises a bed 1 forming thelowest part, a column 2 fixed on the upper surface of the bed 1, a firstsaddle 4 slidably-movably guided in vertical direction f1 through a pairof vertical guide route means 3A, 3B provided to the front surface ofthe column 2, a second saddle 6 slidably-movably guided in lateraldirection f2 through a pair of lateral guide route means 5A, 5B, 5Cprovided to three positions of the front upper and lower positions andthe rear lower position of the first saddle 4, and a spindle head 8slidably-movably guided in longitudinal direction f3 through a pair oflongitudinal guide route means 7A, 7B provided to the second saddle 6.

[0019] An explanation follows about the above-mentioned components.

[0020] The bed 1 is formed into a box structure out of steel plates.Supporting members 9, 9 for fixing a not-illustrated worktable are fixedon the top of the bed 1 in front of the column 2.

[0021] The column 2 comprises one pair of right and left vertical parts2 a, 2 a and one pair of upper and lower lateral parts 2 b, 2 b,consisting chiefly of a rectangular frame body having a comparativelarge space “a” on the central inside. Motor-tables 2 d, 2 d areprovided on right and left ends of the upper lateral part 2 b.

[0022] Servomotors 10, 10 for vertically driving the first saddle 4 arefixed on the motor-tables 2 d, 2 d. Bearing members 12 a, 12 b forrotatively supporting vertical screw axes 11, 11 are fixed on the frontright and left positions of the right and left vertical parts 2 a, 2 aand near the servomotors 10, 10, respectively. Here, the vertical screwaxes 11, 11 combine with output axes of the servomotors 10, 10.

[0023] The first saddle 4, as shown in FIGS. 1, 2, 4, comprises one pairof right and left lateral parts 4 a, 4 b each having a rectangularcross-section and one pair of upper and lower vertical parts 4 c, 4 ceach having a rectangular cross-section, consisting chiefly of arectangular frame body made of fettling steel having a comparative largelongitudinal space “b” on its central inside. In this case, the size ofthe first saddle 4 at front sight is accepted in the front of the column2 and projections 4 d, 4 d are provided to the rear upper and lowerpositions backwardly as shown in FIG. 1. Besides, nut bodies 13, 13 forbeing inserted into the vertical screw axes 11, 11 are fixed on theright and left ends of the upper projection 4 d.

[0024] A servomotor 14 for laterally driving the second saddle 6 isfixed on the front right end part of the upper lateral part 4 a. Bearingmembers 16 a, 16 b for rotatively supporting a lateral screw axis 15 arefixed on the front left end part of the lateral part 4 a and near theservomotor 14. Here, the lateral screw axis 15 combines with an outputaxis of the servomotor 14.

[0025] The second saddle 6, as shown in FIGS. 4, 5, comprises one pairof right and left lateral parts 6 a, 6 b each having a rectangularcross-section and one pair of upper and lower vertical parts 6 c, 6 ceach having a rectangular cross-section, consisting chiefly of avertical rectangular frame body made of fettling steel having alongitudinal space “c” into which the spindle head 8 is inserted on itscentral inside. Besides, the size of the second saddle 6 at front sightis accepted in the front of the first saddle 4 and a spindle headsupporting member 17 having right and left side surfaces 17 a, 17 a anda horizontal surface 17 b is integrally provided to the rear lowerposition as shown in FIG. 2. Moreover, a motor-table 18 is fixed on therear end surface of the supporting member 17 so as to extend backward,and a nut body 19 for receiving the lateral screw axis 15 is fixed onthe top of the upper lateral part 6 a.

[0026] A servomotor 20 for moving the spindle head 8 in longitudinaldirection f3 is fixed on the rear end surface of the motor-table 18. Abearing member 21 for rotatively supporting a not-illustrated spindlelongitudinal screw axis combining an output axis of the servomotor 20 isfixed on the front and rear positions in the center of the width of thehorizontal surface part 17 b as shown in FIG. 2.

[0027] The spindle head 8 has a head frame 23 for rotatively supportinga longitudinal spindle 22 and a not-illustrated driving motor forrotating the spindle 22 is provided thereinside. A not-illustrated nutbody for receiving the spindle longitudinal screw axis is fixed on themiddle of the longitudinal length in the center of the width of the headframe 23.

[0028] Next, an explanation follows about each of the guide route means3A, 3B, 5A, 5B, 5C, 7A, 7B.

[0029] Any of the guide route means 3A, 3B, 5A, 5B, 5C, 7A, 7B is calleda liner motion bearing and well known. As shown in FIG. 6, thesecomprise a straight route member 24, interfitting members 25, andengaging means 26, respectively. The interfitting members 25 slidablymove with fitted in the route member 24. Besides, the engaging means 26make possible smooth relative sliding of the route members 24 and theinterfitting members 25, where separation of the route members 24 andthe interfitting members 25 is restricted.

[0030] An explanation will follow about each component. A route member24 is made a rail member having a rectangular cross-section, forminglinear grooves 27 a, 27 b, 27 c, 27 d each having a semicircularcross-section on the upper positions of the right and left sides and theright and left end positions of the top thereof.

[0031] An interfitting member 25 is made a comparative short memberhaving an angular C letter shape comprising right and left side parts 25a, 25 b and a center part 25 c. Here, the center part 25 c combines theright side part 25 a and the left side part 25 b. Linear grooves 28 a,28 b, 28 c, 28 d are formed on the insides of the side surface parts 25a, 25 b and the center part 25 c so as to be correspondent to the lineargrooves 27 a, 27 b, 27 c, 27 d in this order respectively. Partial flatcircular transfer passages 28 a′, 28 b′, 28 c′, 28 d′ are respectivelyprovided to the linear grooves 28 a, 28 b, 28 c, 28 d to open both endsthereof. Here, the transfer passages 28 a′, 28 b′, 28 c′, 28 d′ areintegrated with the linear grooves 27 a, 27 b, 27 c, 27 d and the lineargrooves 28 a, 28 b, 28 c, 28 d to form closed flat circular passages 29a, 29 b, 29 c, 29 d, respectively.

[0032] An engaging member 26 comprises a large number of spheres 30, andis fitly inserted in each of the closed flat circular passages 29 a, 29b, 29 c, 29 d in a single line and closely in the state where theinterfitting member 25 is fitted in the rail member 24.

[0033] In the guide route means 3A, the first rail member 24 is fixed onthe front left end part of the column 2 in a vertical single line andthe interfitting members 25 for being fitted in the first rail member 24are fixed on the upper and lower positions of the left end part of thefirst saddle 4. In the guide route means 3B, the second rail member 24is fixed on the front right end part the column 2 in a vertical singleline and the interfitting members 25 for being fitted in the second railmember 24 are fixed on the upper and lower positions of the right endpart of the first saddle 4. Here, the guide route means 3A, 3B move thefirst saddle 4 in vertical direction f1.

[0034] In the guide route means 5A, the third rail member 24 is fixed onthe front of the upper lateral part 4 a of the first saddle 4 in alateral single line and the interfitting members 25 for being fitted inthe third rail member 24 are fixed on the right and left end positionsof the upper lateral part 6 a of the second saddle 6. In the guide routemeans 5B, the fourth rail member 24 is fixed on the front of the lowerlateral part 4 b of the first saddle 4 in a lateral single line and theinterfitting members 25 for being fitted in the fourth rail member 24are fixed on the right and left end positions of the lower lateral part6 b of the second saddle 6. In the guide route means 5C, the fifth railmember 24 is fixed on the rear of the lower lateral part 4 b of thefirst saddle 4 in a lateral single line and a single interfitting member25 for being fitted in the fifth rail member 24 is fixed on a projectingpart 17 c provided to the bottom of the supporting member 17 of thesecond saddle 6. Here, the guide route means 5A, 5B, 5C move the secondsaddle 6 in lateral direction f2.

[0035] In the guide route means 7A, the sixth rail member 24 is fixed onthe lower left end part of the head frame 23 in a longitudinal singleline and the interfitting members 25 for being fitted in the sixth railmember 24 are fixed on the front and rear ends of the left end part ofthe top of the supporting member 17. In the guide route means 7B, theseventh rail member 24 is fixed on the lower right end part of the headframe 23 in a longitudinal single line and the interfitting members 25for being fitted in the seventh rail member 24 are fixed on the frontand rear ends of the upper right end part of the supporting member 17.Here, the guide route means 7A, 7B move the spindle head 8 inlongitudinal direction f3.

[0036] The following not-illustrated architectures are added in order toform a machining center on the basis of the above-mentionedarchitectures. That is, there are provided a tool magazine forcontaining a large number of tools, an automatic tool exchanger foroperating so as to receive a tool from the tool magazine and fitlyinsert it in the tip of the spindle 22 or conversely so as to pull itout the tip of the spindle 22 and put back it to the tool magazine, andan enclosure for covering the whole of structures on the bed 1 inaccordance with the necessity.

[0037] Next an explanation will follow about an operation of the machinetool related to the invention. The first saddle 4 is moved in verticaldirection f1 by rotation of the servomotor 10, 10, the second saddle 6is moved in lateral direction f2 by rotation of the servomotor 14, andthe spindle head 8 is moved in longitudinal direction f3 by rotation ofthe servomotor 20. Therefore, the spindle 22 can move toward an optionalposition of three-axis direction.

[0038] When the spindle 22 moves like this and a driving motor of a tool“t” fitly installed to the tip thereof rotatively operates, a work fixedon the not-illustrated worktable can be machined.

[0039] The first saddle 4 is guided and vertically moved by the firstand the second rail members 24, 24 in the guide route means 3A, 3B andtwo upper and lower interfitting members 25, 25 fitted in these railmembers 24, 24. In this case, since the vertical size and the horizontalsize of the first saddle 4 are comparatively large, the first saddle 4moves stably in the state where there is little inclination displacementdue to component floating of the guide route means 3A, 3B.

[0040] Besides, the second saddle 6 is guided by the third and thefourth rail members 24, 24 in the guide route means 5A, 5B of the frontof the first saddle 4 and two right and left interfitting members 25, 25fitted in these rail members 24, 24. Simultaneously, the second saddle 6is guided and laterally moved by the fifth rail member 24 in the guideroute means 5C of the rear of the first saddle 4 and a singleinterfitting member 25 fitted in this rail member 24. In this case,since three parts of the second saddle 6 are guided by three guide routemeans 5A, 5B, 5C having proper intervals each other, the second saddle 6moves stably in the state where inclination displacement of alldirection due to component floating of the guide route means 5A, 5B, 5Cis effectively prevented.

[0041] Moreover the spindle head 8 is guided and longitudinally moved bythe sixth and the seventh rail members 24, 24 in the guide route means7A, 7B and front and rear interfitting members 25, 25 fitted in theserail members 24, 24. In this case, the spindle head 8 moves stably inthe state where inclination displacement due to component floating ofthe guide route means 7A, 7B is hard to happen by the self-weight.

[0042] Besides, according to the machining situation of a work, thespindle head 8 may be greatly sent out forward to the second saddle 6 asshown in FIG. 7. In this case, in a longitudinal move process of thespindle head 8, the second saddle 6 obtains the moment for changing anaction direction of force to reciprocal direction or to various sizes.

[0043] However, three guide route means 5A, 5B, 5C for guiding thesecond saddle 6 act so as to restrict the inclination displacement dueto the moment effectively. That is, when the second saddle 6 tends toincline toward either side of front and rear, either of two guide routemeans 5B, 5C comes to approach the interfitting members 25 and the railmembers 24. Therefore, the engaging means 26 come to counter veryeffectively to such displacement.

[0044] Such restriction in the inclination displacement of the secondsaddle 2 effectively prevents the spindle head 8 from vibrating, andenables a high-accurate machining.

[0045] The above-mentioned embodiment will be modified as follows.

[0046] Instead of providing a single interfitting member 25 on thecenter of the width of the projecting part 17 c of the bottom of thesupporting member 17, the interfitting members 25, 25 to be fitted inthe seventh rail member 24 may be provided to the right and left endparts of the projecting part 17 c respectively. According to this, theinclination displacement of the second saddle 6 due to the componentfloating is restricted more effectively in comparison with the casewhere a single interfitting member 25 is provided to the center of thewidth of the projecting part 17 c.

[0047] Instead of providing the guide route means 5C to the rear lowerposition of the first saddle 7, the guide route means may be providedeach of the rear upper and lower positions of the first saddle 7.According to this, the inclination displacement of the second saddle 6due to the component floating is restricted more effectively incomparison with the case where the guide route means 5C only is providedto the rear of the first saddle 4.

[0048] The spheres 30 of the guide route means 3A, 3B, 5A, 5B, 5C, 7A,7B may be altered to rollers. In this case, the closed flat circularpassages 29 a, 29 b, 29 c, 29 d must be deformed in accordance with therollers. According to this too, the same action as the case where it isbased on the spheres 30 is obtained.

[0049] The rail members 24 of the guide route means 3A, 3B, 5A, 5B, 5C,7A, 7B and the interfitting members 25 can also do the required actionwithout the engaging means 26 such as the spheres 30 and the rollers.For example, the cross-section of interfitting member 25 is formed ininner-spread such as a C letter shape, and the rail members 24 areclosely inserted into the inside space of the C letter shape. Accordingto this too, the required guidance action is obtained by an adequatelubricating means.

[0050] Industrially Applicable Utility

[0051] According to the invention, the following effects can beobtained.

[0052] According to claim 1, the first saddle guides the second saddlethrough three guide route means. Besides, two opposite guide route meansin longitudinal direction are strictly restricted the longitudinalfloating by the second saddle part between these guide route means.Therefore, the second saddle can secure the position stability at theoptional position within the lateral moving range, thereby preventingthe spindle head from vibrating as well as enabling to carry out ahigh-accurate machining.

[0053] According to claim 2, when reinforcing the bottom of the secondsaddle as a spindle head supporting member, the spindle head supportingmember is used both as a component supporting member of two oppositeguide route means 5B, 5C in longitudinal direction at the lower positionof the first saddle. Therefore, the production cost is decreased and thespindle head supporting member effectively transfers floating controlforce due to two guide route means to the whole second saddle.

[0054] According to claim 3, the guide route means can be easily formedby well-known means. Besides, the second saddle can relatively slide onthe first saddle through the route members and interfitting members inthe state where the floating is restricted.

[0055] According to claim 4, the second saddle can increase in positionstability simply and effectively without accompanying with enlargementof the whole construction of the machine tool.

1. A machine tool comprising: a bed 1; a column 2 fixedly installed onsaid bed 1; a first saddle 4 movably guided by said column 2 in verticaldirection f1; a second saddle 6 movably guided by said first saddle 4 inlateral direction f2; and a spindle head 8 movably guided by said secondsaddle 6 in longitudinal direction f3, wherein guide route means 5A, 5B,5C for guiding the second saddle 6 in lateral direction f2 are formed atthe rear upper and lower positions of the first saddle 4 or either ofthe rear upper and lower positions of the first saddle 4 as well as atthe front upper and lower positions of the first saddle
 4. 2. A machinetool comprising: a bed 1; a column 2 fixedly installed on said bed 1; afirst saddle 4 movably guided by said column 2 in vertical direction f1;a second saddle 6 movably guided by said first saddle 4 in lateraldirection f2; and a spindle head 8 movably guided by said second saddle6 in longitudinal direction f3, wherein guide route means 5A, 5B, 5C forguiding the second saddle 6 in lateral direction f2 are formed at therear lower position of the first saddle 4 as well as at the front upperand lower positions of the first saddle
 4. 3. A machine tool as claimedin claim 1 or 2, wherein the guide route means 5A, 5B, 5C for guidingthe second saddle 6 in lateral direction f2 comprise route members 24fixed on the first saddle 4 or the second saddle 6 and interfittingmembers 25 slidably displaced with fitted in the route members 24, theinterfitting members 25 are fixed on either the second saddle 6 when theroute members 24 are fixed on the first saddle 4 or the first saddle 4when the route members 24 are fixed on the second saddle
 6. 4. A machinetool as claimed in claim 1 or 2, wherein the guide route means 5A, 5B,5C for guiding the second saddle 6 in lateral direction f2 compriseroute members 24 and interfitting members 25 slidably displaced withfitted in the route members 24, two route members 24 are fixed on thefront upper and lower positions of the first saddle 4, a plurality ofinterfitting members 25 fixed on the second saddle 6 are fitted in theseroute members 24, and besides, a route member 24 is fixed on the rearlower position of the first saddle 4, and a singular or pluralinterfitting members 25 fixed on the second saddle 6 are fitted in saidroute member 24.